Hydraulic system



y 1942- H. c. FRENTzL, JR

HYDRAULIC SYSTEM Filed, July 20, 1958 3 Sheets-Sheet l "HHH ATTORNEY.

- y 26, 1942- H. c. FRENTZEL, JR 2,284,413

' HYDRAULIC SYSTEM Filed July 20, 1958 s Sheets-Sheet 2 7, H in? MC 7 73M ATTORNEY y 1942- H. c. FRENTZEL, JR 2,284,413

HYDRAULIC SYSTEM Filed July 2 0, 1938 I 5 Sheets-Sheet 3 ATTORNEY.

Patented May 26, 1942 HYDRAULIC SYSTEM Herman C. Frentzel, Jr.,

signo poratlon of Wisconsin Application July 20, 1938, Serial No. 220,215

1 Claim.

My present invention relates in general to improvements in the art of hydraulically actuating diverse mechanisms associated with avvehicle and for effecting control of the operation of such mechanisms from a remote station, and relates more specifically to improvements in the construction and operation of hydraulic systems for actuating and controlling devices such as exca-' vating and dirt scraping assemblages.

Generally defined, an object of my present invention is to provide an improved hydraulic control and actuating system for vehicular structures Milwaukee, Wis, as-

r to The Hell 00., Milwaukee. Wis., a corveniently manipulable from the tractor drivers seat.

Another specific object of the invention is to provide simple and automatically functioning instrumentalities for constantly removing impuri ties from the liquid of a hydraulic control sysv tem, and for maintaining this liquid clean.

A further specific object of the present invention is to provide an improved pump for circulating liquid such as oil through a hydraulic control and actuating system for devices such as power operated scrapers.

such as road scrapers, which is highly reliable and efficient in operation.

It has heretofore been common commercial practice as shown and described in copending application Serial No. 150,232, filed June 25, 1937, now Patent No. 2,169,946, to elevate the load carrying bowl, and to actuate the front and rear aprons, of a tractor drawn scraper, with the aid of hydraulic Jacks or .hoists which are controllable from a remote station disposed upon the traction vehicle. Such control and actuating systems must not only be rapid and positive in action, but they must also be easily manipulable and dependable in operation. Due to the fact that such hydraulic systems are constantly exposed to severe and adverse conditions of operation, it has heretofore been difficult to insure efficient functioning thereof by preventing dust and grit from fouling the actuating liquid and from thus clogging and scoring the valves, cylinders and pumps. The prior systems were moreover sluggish in action and relatively complicated in structure, thereby requiring considerable and expert attention to maintain the same in efiicient operating condition; and for these reasons many of the previous hydraulic control systems for apparatus of this kind, have been re- 7 placed by less efiicient but relatively simple and dependable mechanical systems such as cables coacting with pulleys or sheaves.

The present invention therefore contemplates the provision of variousimprovements in the details of construction and operation of hydraulic control and actuating systems for scraper assemblages, whereby such systems may be made liquid supply reservoir and hydraulic the valve manipulating levers are convenientlyv Still another specific object of my present invention is to provide an improved scraper control system wherein the control valves are disposed upon the scraper in close proximity to the jacks, while accessible fromthe driver's seat of the tractor; and in which the scraper may be readily attached to or disconnected from the traction vehicle.

An additional specific object of my invention is toprovide a relatively simple but very reliable and durable scraper actuating assemblage of the hydraulic type, which is well protected against damage and which maybe readily maintained in most eflicient operating condition.

These and other specific objects and advantages of myinvention will be apparent from the following detailed description.

A clear conception of the nature of my invention, and of the construction andoperation of hydraulic control systems for scrapers, built in accordance with the improvement, may be had by referring to the drawings accompanying and forming a part of this specification wherein like reference characters designate the same or similar parts in the variousviews. v

Fig. l is a somewhatdiagrammatic part sectional side elevation of a dig and carry scraper assemblage having one of the improved hydraulic control systems associated therewith, and showing the control levers and the circulating pump which are normally mounted upon the traction vehicle;

extremely durable and reliable in operation, and

rapid and positive in action, regardless of the adverse nature of the operating conditions.

One of the more specific objects of my invention is to provide a simple, compact and efficient control valve assemblage, the several valves of which are quickly, easily, and con- Fig. 2 is an enlarged-part sectional side view of one of the control valves of the hydraulic system;

Fig. 3 is a similarly enlarged part sectional top view of the control valve of Fig. 2, showing the actuating cable thereof in dot-and-dash line;

Fig. 4 is a likewise enlarged part sectional side view of the manipulating lever assemblage which to is ordinarily mounted upon the hauling tractor,

showing the motion transmitting cable in dotand-dash lines connected to the valve of Fig. 3;

Fig. 5 is a part sectional and somewhat enlarged, top view of the complete valve assemblage and of the liquid clarifying and supply reservoir formed in the scraper frame;

Fig. 6 is a section through the control valves and reservoir, taken along the irregular line 6-6 of Fig. 5; f

Fig. 7 is a transverse vertical section through the liquid supply reservointaken along the line Fig. 8 is a somewhat diagrammatic central horizontal section through the control valve casing, showing all of the valves in neutral position; 1

Fig. 9 is a vertical section through the casing taken centrally of -one of the control valves and showingthe valve in neutral position;

Fig. 10 is a sectional view similar to that of Fig. 8. but showing one of the valves shifted out of neutral position;

Fig. 11 is another vertical section through the While my invention has been shownherein as having been applied to a particular type of dig and carry scraper assemblage, it is not intended to thereby unnecessarily restrict the scope.

Referring especially to Fig. 1 of the drawings, the dirt moving scraper shown therein comprises in general main frame 16 pivotally supported at its front end upon a draft carriage l1 and having rearwardly extending laterally spaced hollow side arms l6 from which anopen ended load receivlng bowl I! is rigidly suspended; an auxiliary.

I frame 26 having its front end pivotally attached to the rear lower portion of the bowl l6 by means of a pivot shaft 2|, while its rear end is swingably associated with the axle of-the rear supporting wheels 22; a rear apron 26 disposed within and movable alongthe bowl I! by means of lever arms 24 pivotally suspended from the rear upper portion of the main frame and bowl assemblage; a front apron 25 swingably' suspended from the front medial portion of the bowl I 9 and being movable toward and away from the cutting blade 26 which is carried by the front portion of the bowl bottom; independently functioning hydraulic jacks 21, 26', 26

for raising the bowl is, and for operating the rear and front aprons 23, 26, respectively; and a hydraulic control and actuating system for the Jacks 21, 26, 29 including'a liquid supply reservoir 30 formed in the main frame 16, a series of control valves housedin a casing" 3| carried by 'the main frame 16, a series of manually manipulable actuating levers 62 for the control valves, a liquid circulating pump 66, and liquid conductors or tubes 64 and motion transmitting cables for effecting operation from a remote station such as the driver's-seat of the propelling tractor which is attached to the draft carriage l1.

The general construction of the scraper constitutes no part of my present invention, and the several hydraulic hoists or jacks 21, 26, 29 are of relatively standardconstruction. The rear jack 21 may have its cylinder pivotally suspended by means of trunnions from the rear upper portion of the main frame 16, and its piston rod cooperable with the auxiliary frame 26 remote from the pivot shaft 2|, in such manner that when this jack 21 is elongated the bowl I6 and blade 26 will be raised or elevated, whereas contraction of the jack 21 will cause the bowl and blade to descend. The intermediate Jack 26 preferably has its cylinder swingably suspended from the pivot shaft 2|, and its piston rod pivotally attached to the medial portions of the lever arms 24, in a manner to cause the rear apron 26 to move forwardly within the bowl 16 when the Jack 26 is contracted, and to move the apron rearwardly upon elongation of this Jack. The front Jack 26 has its cylinder swingably suspended from the front portion of the main frame I6, and its piston rod pivotally attached to the .front apron 26 so that elongation of. the jack 26 s will move the apron 26 toward-the blade 26,

whereas contraction of this front jack will elevate this apron.

In my present improved hydraulic control and actuating system, the jacks 21, 26, 26 are not the only elements which are carried directly by the scraper assemblage, but the main frame 16 is preferably specially constructed to provide a support for the supply reservoir 66, 'the control valves and most of the liquid conducting tubes 34, and these elements are thoroughly protected from dirt and possible damage. The improvedv liquid supply and clarifyingassemblage is shown in detail in Figs. 5, 6 and 7, and comprises in general the storage reservoir 66 formed directly within the upper front cross-beam of the main frame I6; a pipe or tubular inlet 26 depending into one end of the reservoir 26 above a partition 21 which forms an outlet chamber 66 and a liquid receiving well 66 segregated from the chamber 66'; a relatively high dam 40 and a suc-* cession 'of' lower weirs 4| spanning the lower portion of the reservoir to remote from the well 36;" opposite side conduits 42 connecting the chamber 36 with a well 46 formed adiacent the last weir 4|; a series of drain plugs 44 associated with the reservoir III at the well 28 and between thesuccessive weirs 4|; a venting device 45 communicating with the reservoir above the weirs 4|; 9. baffle wall 46 depending from the top of the reservoir 66 between the vent 46 and the dam 40; and a liquid outlet or discharge pipe 41 extending upwardly from the lower portion vof the chamber 66 through the inlet pipe 36.

3|, and this casing has three similar intermedi-" ate sections 49 and an opposite end section 46, all of which are firmly interconnected to form a the casing 31 which is mounted directly upon the main scraper frame l6.

The details of construction of the improved control valve assemblage are best shown in Figs. 2, 3, 8, 9, 10 and 11, from which it will be apparent that each section 46 of the valve casing 3|, is provided with a. central horizontal through bore within which is located a piston valve 6|. Each of the valves 5| is adapted to control. the flow of liquid to and from one of the jacks 21, 28, 29, and the valves 5| are all identical in construction and are independently manipulable by means of three similar manipulating lever-s62 which are connected to their respective valves Bl by the flexible cables 36, and by compression springs 32' meeting with the ends-of the valves remote from the cables 35. The interior of the valve casing is provided'with a pressure chamber 82 which constantly communicates through an opening -58 in the head 50, with the outlet or pressure side of the pump 33; and which, with the valves all in neutral position, also com= municates with the pipe 38 through the opposite end head 58 in the casing 3!, as shown in Fig. 6. The valve casing Si" is also provided with an exhaust chamber}! which is communicable with the chamber 52 past a spring pressed relief valve 55, and which is constantly in open communication with the pipe 38 through the head 48, regardless of the position of the valves Bl. The interior of the casing II is moreover provided with a series of high pressure ports 58 and with a similarseries of exhaustports 51, one of each of which is communicable with one of the jacks 21, 28, 28; so that if one of the control valves 5| is pulled forwardly from neutral position as shown at the bottom of Fig. 10, the corresponding jack 27, 28 or 29 will have oneof its displacement chambers connnected to pressure and the other to exhaust, whereas movementof the valve 5! rearwardly from neutral by the corresponding spring 82' will connect the 'flrst mentioned displacement chamber of the jack to exhaust and the other to pressure. The .valves 5| are completely balanced as to liquid pressures acting thereon, and the springs 32! which are adjustable in strength, are enclosed within houslugs 58 and may be adjusted with the aid of a socket wrench. applicable through openings in these housings which are normally sealed by plugs it, see Fig. 1i. The cables 35 are adjustably attached to the valves 5! through valve stems it which slidably coact with other housing 6 I, and all of the housings", Mare provided with packings 62 adjacent the ends of the valves 12 are adapted to engage the latches 1: when the levers 32 are thrown in either of their extreme positions. Each of the bearing portions i9 is attached to one of the cables 36 bymeans of an adjustable link 14 coacting with an adlusting collar 15 so as to permit slack in the corresponding cable 32 to be taken up, and the links 14 are provided with adjustable abutments II with which coil springs I1 coact. The springs 11 are housed within and react against casings It secured to the bracket 66, and the assemblage is such that the springs 'I'I maintain the cables 35 taut at all times when the collars I5 and the abutments I! have been properly adjusted. The

manipulating lever assemblage may obviously be applied to. or removed from its support, as a unit, and the several levers 32 are Preferably positioned closely adjacent each other.

The improved liquid circulating pump 33 for delivering liquid under pressure from the reservoir 88 to the several hydraulic jacks 21, 28, 29 is preferably operable by the motor which propeis the tractor, and should therefore be mounted upon the traction vehicle near the levers 32.

The pump 38 is shown in detail in Figs. l2, l3

and 14, and is of the gear type comprising intermeshing gear rotors l9 rotatable within a casing 8d, the opposite sides of. which are provided with similar sealing plates 8! and with outer heads 82, as coacting with the plates 8i. One of the rotors i9 is mounted upon a driving shaft 84 which is drivingly connected to a power the gear 81 may be moved into and out of mesh 5|. It should be noted, that in this improved 33, is'shown in detail in Fig. 4, and comprises the three levers 32 which are mounted for oscillation upon a pivot shaft 83 supported upon a bracket 64. The bracket 5t may be supported upon the tractor preferably within easy reach from the. drivers seat, at any desired anglerand has upper and lower slotted portions which coact respectively with an upper clamping bolt es and with lower positioning j rivets 66. A

take-olfshaft 35 as shown in Fig. 12, by means of a gear 86 fixedly mounted upon the pump shaft 85 and meshing with a gear 8? which is siidably splined to the shaft 85. The shafts 84, .85 are journalledfor rotation in anti-friction bearings carried by the tractor casing 88, and

with the gear 86 by means of a shifter rod as .slidably supported in the casing 88 and having at one end an actuating button or knob .90, and at its opposite end a bracket 9i coacting with an annular groove 92 formed in the hubof the 'gear 81. The medial portion of the shifter rod 89 is provided with spaced grooves '93, 94 with which a ball latch 95 is coopera'ble to position the gear 87 either in active or inactive position.

While the pump 33 when properly assembled and installed, is operable in one direction'only, it may be installed for rotation in either direction, or with the inlet and outlet connections communicating with either end thereof, by virtue x of the improved formation of the casing 80 and spring pressed retaining latch 61 associated with the bolt 85, normally coacts with; a socket 68 to hold the bracket 86 in position, but the bracket may be quickly removed by merely releasing the latch 61. The levers SZ-are provided attheir outer ends with suitable grip knobs, and have their inner ends provided with healing portions 68 having notches it therein and limit stops H, 12 spaced, from the notches 10. Reciprocable spring pressedlatches 13 which are carried by the frame 6t, are adapted to coact with the V- notches It of the respective levers 32 to hold them in neutral position, and the limit stops H,

of theside plates M. The casing 80-15 provided with a displacement chamber 98', within which the gear rotors 19 are operable, and the chamber as has alined ports t! in constant com; munication therewith. Directly adjoining each port 91 is a threaded socket 98 adapted for the reception of a liquid outlet or discharge pipe 99, and directly adjacent each socket 98 is a larger threaded socket I08 adapted for similar reception of a liquid inlet or suction pipe 10!.

Communicating laterally with each of the sockets 8B, is a pair of opposite alined ports mz, one

set of which is open to-the suction side of the pump while the other set is sealed by the insertion of the discharge pipe 98 as clearly indicated in Fig. 13, and the ports I02 are in open communication with openings 13 in the adjacent side plates 8|. The openings I03 are connected by passages lfll'with annular sealing chambers its all formed in the plates 8|, and the chambare it! surround the shafts as and are at all liquid from escaping the pump. bearings I68.

Each of the side plates BI is also provided with opposite side detents lil'l shown in Figs. 13 and 14, which form recesses at the opposite ends of the intermeshing teeth'of the rotors l9 and thereby prevent the rotors from becoming locked due to the confinement of high pressure liquid therebetween; and by providing four of these detents IOI on each plate 8| and by making the plates symmetrical and reversible, one set of the recesses iill will be eifective regardless of the mode of assembly or of the direction of rotation of the pump rotors 19. The suction pipe it! of the pump 93 is normally connected with the liquid supply pipe 61 through the valve casing end head 48 and one of the flexible conducting pipes 34, and the discharge pipe 99 is connected to the port 63 of the opposite casing end head 50 through another of the pipes at, and the tral position as shown in Fig. 8, all ofthe liquid delivered to the chamber 52 through the port E3 is free to escape past the central portions of the valves ii to the return pipe 3| of the reservoir 30. and is delivered into the well 39. As this liquid accumulates in the well 39, it eventually flows over the crest of the dam 40 and over the tops of the weirs II and returns to the chamber 38 through the end well 43 and conduits'fl. This return of the liquid through the basin ab ave the weirs ii is very slow. and any heavy impurities will naturally descend by gravityand will accumulate in the pockets between pump 83 may be provided with a shut-off valve I08 for disconnecting the pump from the hydraulic system. The pipes 84 may also be provided with a rigid section I09 supported upon the-carriage H, in order to prevent these pipes from being damaged by the tractor, and the pipes 34 leadingfrom the valve casing 3| to the rear and intermediate jacks 21, 28 are preferably conv fined within the side arms I! of the main frame I. The valve casing 3i is also preferably cov- Fig. 1.

When the improved hydraulic system has been properly installed upon a scraper assemblage and a tractor and has been supplied with sufficient actuating liquid such as oil, the pump 33 may be connected to or disconnected from the power in Fig. 12. the pump 33 is in operation, and motion is being transmitted thereto from the shaft 85 through the gears 31, O6 to the pump shaft- 84, and the gear rotors "are revolving downwardly toward the discharge pipe #9 as viewed in Fig. 13. The pump 33 is then withdrawing liquid from the reservoir 3] through the chamber 38, pipe 41, valve casing head 33, suction pipe 34 and inlet pipe III, and is forcing the liquid under pressure through the discharge pipe as, pressure pipe 34, and port .53 into the high pressure chamber 52 of the valve casing 3l., When the gear 81 is shifted along the shaft 35 to cause the latch 85 to engage the groove 94, the pump 33 will stop and the circulation of liquid will naturally cease, or the circulation may also be stopped by closing the valve I08. During such normal operation of the pump 33, any liquid which escapes from the pump displacement chamber 36 past the shafts II. will enter the chambers I" in the side plates II, and since these chambers I" are all connected to the suction side of the pump through the passages I,

ered and protected by a shield 0 as shown in venting ingress of dust, and when none of the jacks 21, 28, 29 are in operation, the pump 33 is I practically relieved of pressure except as required to circulate the liquid through the valve casingli, reservoir 30 and conductor pipes 34.

As previously indicated. any of the lacks 21, 28, 29 may be operated independently of the others, and simultaneously therewith if so desired, by merely manipulating the lever 32 corresponding to the jack or jacks which is to be operated. When a lever 32 is swung from neutral position as shown in Fig. 4, to bring the stop Ii thereof into engagement with the latch 13, the corresponding valve 5i will be moved forwardly by a direct pull on the. cable 35 thereof assisted by the spring 11. to the position shown in Fig. 11,,thereby cutting oi! the free flow of liquid' from the pressure chamber 52 to the reservoir 30, while at the same time connecting the port 83 to the high pressure chamber 52 and simultaneously connecting the port 51 with the lower pressure or exhaust chamber 54. The piston of the corresponding jack 2], 28, 28 will then be subjected to high pressure liquid onone side, and to exhaust on the other side, and will. move in the desired direction. In order to re-- turn the jack piston to the initial position, it is only necessary to swing the corresponding control lever 32 in the opposite direction until the abutment stop I2 engages the latch 13, whereupon the corresponding valve SI will be moved rearwardly by the action of the corresponding .spring 32' until the port I56 .is connected to latch 32 in engagement with the notch III thereopenings I08 and ports I02 adjacent the inlet of. In the event that the pressure within the chamber 32 becomes excessive for any reason whatsover, the relief valve will automatically operate to relieve the excessive pressure and to permit the liquid to escape to the low pressure chamber 54. In the event that one jack is being operated by manipulation of its corresponding valve 5i, and 'it then becomes desirable to operate any of the other jacks, such operation may still be effected with the improved vaivef mechanism, since liquid under pressure may still i be delivered from the chamber 52 of the valve casing 3! to such other jack. This will be clearly apparent from Fig. 10, wherein liquid under pressure may be delivered to either of the upper valves 5|, regardless of the seating of the lower valve 5|. It will thus be apparent that any one or more of the jacks 21, 28, 29 may be operated in either direction, either independently of or simultaneously with others,-and the capacity of the pump 33'should of course be suificie'nt to take careof all of the jacks.

It is also'to be observed that each of the valves 5| is completely balanced as to liquid pressures thereon, and that these valves may be operated in either direction without destroying the tautness of the cables 35. The valves 5| are movable in one direction by the pull on the corresponding levers 32 aided bythe springs TI and are movable in the opposite directions by means of the springs 32' which should be of sufilcient strength to overcome the action of the springs 11. The various parts of the apparatus are susmerely'the pump and control levers are located upon the traction vehicle. The pump and the control levers may, however, be conveniently 8,131 plied to or removed from the traction vehicle, and all portions of the mechanism are eiiectively protected against possible damage due to normal use of the scraper assemblage. While I have shown only three control valves operating in conjunction with only three hydraulic jacks, the

, number of these devices may be increased or diminished as desired, by merely adding additional valve casing sections 40 and valves 5|, together with control levers 32 for these additional valves.

.An important feature of the present invention is the mechanism for operating the valves with the aid of cables which are constantly in tension. ,The improved control lever assembly is also important as is the specific construction of the valves themselves. clarifying apparatus associated with the supply reservoir 30 operates to effectively maintain the liquid in clean condition, thereby preventing possible scoring of the valves and jack cylinders, and the improved pump construction may be The improved liquid readily assembled and installed without danger of having the ports I02 improperly connected. It will be apparent that the pump may be operated in either direction. and the pipes 09, 501 may be connected to either side thereof, and the side plates 8| may be installed in any desired manner, without disturbing the emciency of the pump. The improved construction of these side plates 0| with the conduits I05 and bleeder passages l04 which withdraw lubricant from the bearings I06 rather than permitting oil from the hydraulic system to enter these bearings, is very important, and it should be noted that this construction protects the bearings I06 against .ingress of grit. The side plates 8| are of suiilcient thickness to-prevent deflection due to the hydraulic pressure in the circulating system, and wear on. these plates is therefore reduced to a minimum, While the pump has been shown herein as being operable by the tractor propelling motor, a separate motor may also be used for propelling the pump, without departing from the present invention. The improved system has proven highly satisfactory and successful in actual commercial use, especially as applied to a road scraper of the type shown herein, and the system may obviously be furnished at moderate cost and is extremely reliable in actual operation. It has also been found desirable in order to prevent settling of the scraper bowl and due to the necessary clearance in the control valve 5| for the bowl elevating hoist or jack 21, to provide a check valve for positively retaining the hydraulic pressure in the cylinder of the Jack 27 when its control valve is in neutral position. This check valve may be inserted in the return line for the jack 2! in advance of its control valve 5|, and the check valve may be operable by high pressure fluid in the system so'as to prevent oil from escaping from the jack cylinder when it is desired to retain the scraper bowl elevated.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the precise mode of use herein shown and described. for various modifications within the sc0pe of the claim, may occur to persons skilled in the art.

I claim:

I A reservoir clarifying structure for a hydraulic system, comprising a receptacle having a separated inlet and an outlet, means within the receptacle forming receiving and outlet chambers, a relatively high dam and spaced lower weirs within the receiving chamber, and longitudinal partitions along opposite lower interior side portions of the receptacle providing conduits between the receiving and outlet chambers.

, HERMAN C. FRENTZEL, JR. 

